UFO'S of UAP'S, ASTRONOMIE, RUIMTEVAART, ARCHEOLOGIE, OUDHEIDKUNDE, SF-SNUFJES EN ANDERE ESOTERISCHE WETENSCHAPPEN

Ajoint investigation between scientists from the Center for SETI Research at the SETI Institute and METI International resulted in the discovery of exactly zero radio transmissions emanating from KIC 8462852, aka Tabby’s Star, aka that “alien megastructures” star everyone freaked out about late last year. According to new findings published in The Astrophysical Journal Letters, we still haven’t found signs of extraterrestrial intelligence. Our cold streak continues.

In case you don’t remember, there was a big hooplah last fall when Jason Wright, an astronomer at Penn State University, dropped a small suggestion that strange stellar light patterns glowing from Tabby’s Star, nearly 1,500 light-years away from Earth, were caused by “alien megastructures,” a catchall phrase for materials artificially placed in orbit. Since then, study after study has basically put that hypothesis to rest, with more reasonable ideas like a family of weird cometsgarnering more and more support based on new data.

But science is about making confirmations, so the dutiful scientists at the SETI Institute and METI international came together and used the Boquete Optical SETI Observatory in Panama to determine whether or not the strange dimming patterns were caused by intelligent extraterrestrials, as well as use the Allen Telescope Array in California to measure whether the star system was spewing out any radio signals indicative of advanced technology.

“We were looking to see if there are intentional laser signals being beamed at us,” says METI International research and study coauthor Douglas Vakoch. He tells Inverse he and his colleagues were looking for the kinds of signs of technology that us humans on Earth might be capable of building and using to broadcast our presence to the rest of the universe.

Unfortunately, they did not find any radio signals, and the optical signals found were less than encouraging. No optical signal of a particular period pattern was measured, and the power of the light pulsing from Tabby’s Star didn’t seem characteristic of a laser signal. “If there is a large laser facility kicking out signals of 5 mega-joules or stronger, we would have been able to detect those,” says Vakoch. “We didn’t.”

Vakoch emphasizes that the results don’t totally discount alien life living in the star system. He and his team were using Boquete during Panama’s rainy season — “the worst possible time,” he says. He acknowledges that the results “don’t say for sure there aren’t extraterrestrials out there.” It’s always possible E.T. is sending weaker signals out or exhibiting patterns stretching across a larger timeframe.

“But we can say that within the scenario where we could have possibly gotten a signal, we didn’t get one,” says Vakoch.

Disheartening, sure, but there’s a strong silver lining to the new findings. While SETI research around the world centers in large part around the measure of radio signals, the new investigation allowed the scientists to flex their optics muscles and get practice at looking for signs of E.T. across other frequencies as well. “If we get a signal, there may be different sources of information at different frequencies, so we need to be ready to jump on that,” said Vakoch.

Moreover, the study demonstrated the feasibility of using even a modest-sized optical telescope to conduct SETI observations. This runs counter to the whole “bigger is better” mentality that permeates space science, and Vakoch thinks the new methodological approaches he and his colleagues outline in their paper illustrate a new model for doing SETI research that is more efficient and sustainable. He says a major goal of METI International, after all, is to answer “how do we sustain the search going forward” as funding for these types of projects drop or become thinned out over more and more initiatives.

“We still don’t have a natural explanation for what is going on” with Tabby’s Star, says Vakoch. And he doesn’t find that particularly discouraging. “This is the type of ambiguity we can expect if we really got a signal from E.T. It will be a slow unfolding and grappling of the data. So we continue to search for answers.”

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Neanderthals and modern humans interbred long ago, but evolution has purged many of our caveman relative's genes from modern human genomes, a new study finds.

Neanderthals were the closest extinct relatives of modern humans. Previous research suggested that modern humans migrating out of Africa encountered and interbred with Neanderthals tens of thousands of years ago.

"We know that the ancestors of modern Europeans and Asians mated with Neanderthals, and as a result, the modern-day descendants of those people have some small amount of Neanderthal DNA in their genomes," said study lead author Ivan Juric, an evolutionary biologist at the University of California, Davis. [In Photos: Neanderthal Burials Uncovered]

Findings published in 2014 suggested that the hybrid descendants of such interbreeding might have benefited from some of these Neanderthal genes. For instance, Neanderthal mutations may help modern European immune systems dampen inflammation.

However, nowadays, Neanderthal genetic material makes up only about 1.5 to 2.1 percent of the genomes of people outside Africa, according to the draft sequence of the Neanderthal genome published in 2010. That means some of this genetic material was lost over time. To better understand why this evolutionary purge occurred, Juric and his colleagues examined where Neanderthal DNA was found in the modern human genome.

If offspring of modern humans and Neanderthals had Neanderthal DNA segments that possessed some so-called deleterious alleles — that is, harmful genetic variants — "then they'd be less likely to have kids, and so less likely to pass on those Neanderthal segments to future generations," Juric told Live Science.

In this way, the evolutionary mechanism of natural selection ensures that "over time, Neanderthal segments containing deleterious alleles get removed from populations faster than Neanderthal segments not containing deleterious variants," Juric said.

Previous research found that there is less Neanderthal DNA in regions close to genes than in the relatively inactive regions between genes. This suggests that natural selection weeded out Neanderthal variants of those genes, Juric said.

Juric and his colleagues developed a computer model that simulated the effects of natural selection on the distance between segments of Neanderthal DNA and modern human genes. Given the amount of time that has passed between interbreeding between Neanderthals and modern humans and the amounts and locations of Neanderthal DNA now found in the modern human genome, their findings suggest that many Neanderthal gene variants that entered the modern human genome after Neanderthals and modern humans interbred were "weakly deleterious" — that is, "they are being slowly removed by natural selection," Juric said.

The researchers suggested that many mildly negative gene variants, or alleles, were able to persist in Neanderthals because Neanderthals had much smaller populations than modern humans. However, when these gene variants made their way into modern humans, modern humans' larger populations — and thus bigger gene pools — were better at winnowing out these deleterious alleles.

"I find it fascinating to think that if the Neanderthals had reached larger population sizes in Europe, or if modern human populations had grown slower, some of us today would probably carry a lot more Neanderthal ancestry in our genome," Juric said in a statement.

Future research could investigate which genetic variants from extinct relatives of modern humans were weeded out of the modern human genomes. "I would love to know which exact Neanderthal alleles were selected against," Juric said. "Once we know more about the genes involved, we can ask what those genes do and what traits they are involved with in modern humans. Then, we might be able to make some guesses about the traits of those early human-Neanderthal hybrids."

The scientists detailed their findingsonline Nov. 8 in the journal PLOS Genetics.

Original article on Live Science.